1. Field of the Invention
The present invention relates to an information storage medium and a recording/reproducing apparatus and method that can flexibly operate a middle area of the information storage medium when the information storage medium is finalized.
2. Related Art
Information storage media, such as optical disks, are widely used in optical pickup devices which record information thereon or reproduce information therefrom in a contactless manner. Such optical disks can be classified as either compact disks (CDs) or digital versatile disks (DVD) according to data recording capacity. Examples of optical disks that can be recorded, deleted, and reproduced include 650 MB CD-Rs, CD-rewritables (RWs), 4.7 GB DVD+R/RWs, DVD-random access memories (RAMs), and DVD-R/RWs. Examples of optical disks that are dedicated for data reproduction include 650 MB CDs and 4.7 GB DVD-ROMs. Further, next-generation high density DVDs or Blu-ray Discs (BDs) having a recording capacity of 15 GB or greater are under development.
FIG. 1A illustrates the structure of an example rewritable optical disk. FIG. 1B illustrates the structure of an example optical disk for data reproduction. As shown in FIG. 1A, the rewritable optical disk 100A includes a lead-in area 110, which is generally located near the inner circumference of the optical disk 100A, a lead-out area 120, which is generally located near the outer circumference of the optical disk 100A, and a user data area 130, which is located between the lead-in and lead-out areas 110 and 120 and in which user data is recorded. Similarly, the optical disk 100B for data reproduction, as shown in FIG. 1B, also includes a lead-in area 110, which is generally located near the inner circumference of the optical disk 100A, a lead-out area 120, which is generally located near the outer circumference of the optical disk 100A, and a user data area 130, which is located between the lead-in and lead-out areas 110 and 120 and in which user data is recorded. As shown in FIG. 1A and FIG. 1B, the lead-in area 110 and in the lead-out area 120 of both the rewritable optical disk 100A and the optical disk for data reproduction 100B are almost identical. However, the lead-in area 110 of the rewritable optical disk 100A, as shown in FIG. 1A, includes an optimum power test zone for optimum power control (OPC). Such an optimum power test zone is not required in the case of the optical disk for data reproduction 100B, as shown in FIG. 1B.
The optical power control (OPC) is utilized to determine the best recording laser power setting for each optical disk and a recording and/or reproducing apparatus combination. Specifically, such an OPC is about recording user data in the optimum power test zone using various recording powers before the recording and/or reproducing apparatus records the user data on the rewritable optical disk to determine an optimum recording power for recording data on an optical disk, such as CD-R, CD-R/RW, DVD-R/RW, HD-DVD.
In the rewritable optical disk 100A, as shown in FIG. 1A, the optimum power test zone of a fixed size is allocated at a fixed location. Thus, it is not possible to allocate an additional optimum power test zone or increase the size of the optimum power test zone on the optical disk. Since the recording characteristics of an optical disk including a plurality of recording layers depend on the recording layer in which data is recorded first, the optimum power test zone for OPC should be placed in consideration of the recording characteristics of the optical disk. In particular, when the optimum power test zone is allocated in an outer circumferential area of the optical disk, the recording characteristics of the outer circumferential area must be considered.
The recording characteristics of the outer circumferential area of the optical disk including a plurality of recording layers are poorer than those of an outer circumferential area of an optical disk having a single recording layer, which must also be taken into consideration. Similarly, in addition to the optimum power test zone, when an area for other use purposes is allocated in the outer circumferential area of the optical disk, the recording characteristics of the outer circumferential area must also be considered.
For an optical disk comprising two recording layers L1 and L2, the recording characteristics of the recording layer L2 depends on whether data has been recorded in the recording layer L1 close to a pickup unit. In the case of sequential data recording, data is always recorded first in the recording layer L1. When test data is recorded in the optimum power test zone for OPC included in the recording layer L2, a pre-recorded zone should be allocated in the recording layer L1 in advance since the test data must be recorded first in the recording layer L1.
However, allocation of such a pre-recorded zone increases the manufacturing cost of a data recording and/or reproducing apparatus. Hence, the allocation of the pre-recorded zone and the optimum power test zone for OPC needs to be selectively determined. In this case, the optical disk requires an OPC zone at a predetermined location and an OPC zone that can selectively be used by a drive system.
In terms of time, to effectively record data in the outer circumferential area of an optical disk having two recording layers L1 and L2, the position of a middle area in the optical disk may be different from the same position in an optical disk having a single recording layer. In this case, diverse layouts of the optical disk having the two recording layers L1 and L2 are required to allocate the optimum power test zone for OPC in the outer circumferential area of the optical disk.
Since the middle area is used when a pickup unit of a drive system moves among two or more recording layers, the middle area must be longer than a predetermined length to achieve a desired jump performance. When the optical disk having the structure described above is finalized to stably determine the middle area, the middle area may be insufficient for data recording.
Accordingly, there is a need for an information storage medium comprising multiple recording layers provided with at least one middle area used by a recording and/or reproducing apparatus to move among the recording layers such that the middle area can be flexibly extended when the information storage medium is finalized. Also needed is a recording and/or reproducing apparatus provided with the ability to extend the middle area of an information storage medium comprising two or more recording layers and to record data of a predetermined pattern in the extended middle area.